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Re: Nematode killer selection

  • Subject: Re: Nematode killer selection
  • From: "W. George Schmid" hostahill@Bellsouth.net
  • Date: Tue, 30 Sep 2003 14:12:09 -0400

Hi Andrew, All,
The most important statement of Andrew is: Take it easy! I have had
nematodes for 30 years and I am happy to just control them. Here the damage
does not show up until August (in most cases) after the garden tours and
after it has gotten so hot outside you don't want to be there in the first
place. Please don't poison your whole garden just because some plant are
affected with nematodes. Dig the things up, isolate them in the lowest point
of your garden, and see what happens. They can't swim upstream. Consider
your neighbor too. To sterilize your entire property is madness! Learn to
live with pests and use organic methods first (so far not available for fol.
nematodes). Then switch to the heavy stuff. I find that I can control (not
eradicate!) foliar nematodes with systemic rose care applied sparingly three
or four times in spring, first when they eyes are just popping. Then at 2-3
week intervals. until the leaves are unfolded. After that you can apply
Cygon (a bad number but available) with spray once or twice during late
spring, but only to plants that you suspect or have isolated. Stuff like
Zerotol will kill everything in the soil, good and bad. During our 4-year
drought just past I hardly saw any nematodes. The 2003 spring rains brought
them out in abundance but I refuse to get panicky. Hey, it's nature at
work!!! Some gardeners buy organic food then effectively poison the ground
they garden on and in. Above all, read the stuff in THJ written about it and
on the Web. A lot of good stuff there. And apply your knowledge (read
selected poisons) with a grain of respect for our environment. By the way, I
have never lost a hosta due to foliar nematode damage! George

W. George Schmid
Hosta Hill - Tucker Georgia USA
Zone 7a - 1188 feet AMSL
84-12'-30" West_33-51' North
Outgoing e-mail virus checked by NAV
----- Original Message -----
From: "Andrew Lietzow" <alietzow@myfamily.com>
To: <HMinnesota@aol.com>
Cc: <hosta-open@mallorn.com>
Sent: Tuesday, September 30, 2003 1:20 PM
Subject: RE: Nematode killer selection

> Dear HMinnesota / Tom Carlson,
> I'll take a stab at answering these because many are busy battening down
the hatches, getting ready for winter.  Please note that if you are
commercial grower, your treatment regimen and response would be totally
different than if you're a casual gardener.  Of course, you already knew
> 1)  If you had one chemical to pick to kill every nematode in your garden
by drenching, which would you pick?
> Nemacur 3, Zero Tol, Diazinon 4E -- in liquid form, if available (to make
drenching easier) and in that order.   Some are restricted use chemicals,
and not readily available in IA.  I presume the same problems, or worse, for
MN.  Zero Tol appears to be readily available, is comparable in performance
with Diazinon 4E, doesn't require an applicators license, and thus it seems
like the obvious choice.
> RE>>Nemacur & Vydate & Cygon - Ref. article "Control of Foliar Nematodes
on Hosta", The Hosta Journal, Vol 30, No 1 (Spring 1999), pgs. 78-83.
Unfortunately, Nemacur 3 is not available in Iowa (only Nemacur 15g and I'm
not so sure of that any more).  Zerotol should be readily available.  Vydate
and Nemacur are restricted use chemicals (don't know about Cygon) so there
are hurdles you have to jump through to obtain these chemicals.
> RE:>>Terrachlor & Peroxide & Pylon - I am not familiar with these.  Ask
your nursery supply places for their experience.   Hydrogen DI-oxide is the
active ingredient in Zero Tol, and I believe others have stated that
Peroxide is ineffective.
> RE:>>Zero Tol 2% solution - Both Parwinder Grewal and Bob Solberg have
been quoted as proponents of Zero Tol.  I have no experience with this
chemical but it seems to me that if one CAN purchase this product WITHOUT
obtaining a chemical applicators license, this would be the effective
treatment of choice.
> 2) >> If you select something that sterilizes the soil, will it ever come
> Sterilizes the soil?  You mean like with boiling water?  Well, if you get
the soil so hot that it becomes "sterile" certainly all plants will die.
For chemicals, I suppose if the concentrations are outside the
recommendation dosage, living organisms will also die.  I'm not sure what
you're asking here.
> >>Will it kill trees?
> If you read and follow label directions, trees and plants should not be
adversely affected.  The mechanism for control attacks animals, not plants.
> 3)  If the nematodes live in the plant and you cut off the leaves at the
ground and drench the roots and surrounding soil with one of the above
solutions, will the solution be absorbed into the remaining roots of the
plant and kill the nematodes?
> --------
> Have no experience on this one.  Foliar drenches of Nemacur 3 have caused
necrosis on exposed tissue (ibid.), especially when applied in the hot sun,
so it's probably wise to apply such products during a dormant period, or
with cut back leaves as you mention.   A thorough application is of course
better than a hap-hazard one so reading label instructions will serve you
well. Most IPM protocols state that the goal is not 100% eradication but
effective control.  With nematicides, it's probably more cost effective, and
beneficial to the environment, to achieve 80-90% control than 100%.
> As an aside, for our garden guests to expect 100% flawless leaves, aren't
we better off recommending that in their gardens they plant silk or plastic
versions of Hosta?  :-) While I LOVE a flawless Hosta as much as anyone, if
I set my expectations that high, most of the time I'm going to be very
disappointed with my garden.  I think we do some disservice to the potential
buying public when we set our standards, and their expectations, so high.
Here in the Midwest, we have hail storms that are a bigger problem than
nematodes, so I just refuse to get too excited about these pests.
> Why are we "freaking out" about nematodes?   I've seen people reject
plants that had burn holes from water droplets on their leaves, and they act
like the plant will be cursed forever instead of just one season.   Are
nematodes a "quarantined" pest?   Anyone know?  Of course, when you're
running a nursery you've got to jump through a lot of hoops which disappear
if the burden is placed on the home gardener.
> 4)  I don't know how many of the above chemicals are available in
> I would imagine most of them.  Call your local chem and nursery supply
houses.  They love to sell chemicals and cure pest infestations in the
> 5)  If you leave a plant in a 2% Zero Tol solution, will it kill the
nematodes and not the hosta?
> Find Parwinder Grewal's article in THJ, Vol 32, No. 1, pgs 64-66--this is
a very down to earth article written in easy to understand terms.   My
question to you, however, is, "Why would you want to leave a plant in the
solution"?   Even water will eventually kill the Hosta long before the
nematodes are gone.  I'm sure I'm missing something here.
> >>I agree with previous posters.  I think hosta lovers could benefit by
> creating a database of hostas that get nematodes and those that don't.  I
> think there are some plants that don't get them or at least show the
> Now you're talking about something that is of serious interest to me.
Unfortunately, there is a difference between having a serious interest in
something and having a "passion" for it. :-)  Someone more passionate than I
will have to add these fields into their database.   Maybe Mike Lemke or Lu
Treadway will respond to this, or even our AHS Registrar?
> Personally, I think Ploidy analysis is much more quantifiable, useful, and
easily implemented.  Though a subjective listing or resistance experience of
cultivars against viruses and nematodes might be doable, the problem I see
is that one year a plant will show serious damage and the next year may be
unaffected.  Is this due solely to microclimate issues or is there a genetic
response for resistance being triggered?  How does one quantify a plant's
resistance to disease?  At least with morphology, we have established
> For resistance to pests, it seems that the scale would have to be highly
subjective.    Are there other plant databases that have established such
criteria?  Maybe we could borrow some of their logic and implement same for
the genus 'Hosta'.   Something tells me this is either an all or none
phenomena at best, and data that could be a sliding scale replete with data
that could be very misleading, at worst.    If it could be constructed with
a 1-5 level and understood to be very subjective, there might be some
benefit that could accrue.   What do others think?
> Right now I'm passionate about getting ready for the 2004 AHS Convention,
having but a moderate interest in genetic analysis of nematode resistance
(genes) in Hosta.  I will say that there are many Hosta that appear to
respond to nematode infestation with an increased presence of HS1(pro-1) and
HS2 genes (or whatever resistance genes are present in Hosta).  One year, a
plant will show a significant infestation and the next year the plant is
either nearly immune or the nematodes have on sabbatical (as was the case
for H. William Lachman, H. Summer Joy, H. Dorothy Benedict, H. Crayons, and
others in one area of my garden that had been significantly infected last
year).   Unfortunately, I am a gardener with a penchant for Hosta Science
and not a Hosta Scientist with a penchant for gardening.  :-)
> SO, if you want REAL answers, you'll want to ask your questions of
nematologists or the technical support departments of the Agri-chemical
companies. It's amazing how helpful they will be if you tell them you're
interested in purchasing their products.  I found Bayer Agricultural to be
most helpful but it took several emails and phone calls.  I finally did find
a source for Nemacur that was willing to sell me one bag but it took going
high up in the hierarchy and that bag had to be shipped here from
Mississippi.  If I had wanted a truck load, however, it would have been no
> RE>>Thanks much - I am sure many will benefit from this.
> You're welcome much and  I hope so.  My best "advice", if you could call
it that, is to NOT throw the baby out with the bath water as used to be
recommended.  Let the plant develop it's natural defenses and if it dies,
then you can report that this or that cultivar seems to be a real wimp in
combatting nematodes.   Let us know how you do!
> Andrew Lietzow
> in Des Moines, where we're likely to have our first hard freeze tomorrow
evening--about 8 days ahead of the average first hard freeze date of Oct. 9.
> _____________________________________________________________________
> Get your own family web site at at www.MyFamily.com!
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